Proposed Title 1: - Queen's University

Figure 2.15: Distribution of 207 Pb/ 206 Pb ages for 260 uraninite grains along with the timing of
various uranium mineralization and tectonic events that affected the Beaverlodge area. The
ages are from analysis of grains from different styles of uranium mineralization. Also shown
are the area distribution of supercontinents and major magmatic events in North America.
(e.g Hoffman, 1989; Ernst and Buchan, 2001b; Li et al., 2008)
Lower U-Pb intercept and chemical Pb ages close to 0 Ma (Tables 2.1, 2.2, and 2.3)
are interpreted to record recent fault reactivation and resetting events likely during the
Pleistocene glaciations-related stress fluctuation that caused continental-scale isostatic
readjustments as the upper crust deformed in response to deglaciation and lithospheric
unloading (Adams, 1989; Karlstrom, 2000; Fullerton et al., 2003). Similar ages are also
recorded in uranium deposits in the Athabasca Basin (Alexandre et al., 2005).
These alteration and resetting stages of uraninites and the late Chl 9 , Cal 11 , Qtz 5 and
Hem 9 veins that cut across the fault zones record the effect of late fluid events that have
affected the deposits subsequent to their formation. The late fluid events may represent
incursion and circulation of hydrothermal and meteoric water through the structurally
reactivated fault zones (Kotzer and Kyser, 1995), suggesting that the fault zones were
active after deposition of the uranium mineralization and remain zones of preferential fluid
circulation (Fayek and Kyser, 1997).
2.6. CONCLUSIONS
Structural and metamorphic relationships within the Main Ore shear zone and the
Saint Louis fault, and petrographic analysis and geochronological data from various
uranium deposits indicate that the Beaverlodge area records ore-forming systems that
result from a complex history of multiple reactivation and hydrothermal alteration
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